Gas turbine engines typically include a fan section to drive inflowing air, a compressor section to pressurize inflowing air, a combustor section to burn a fuel in the presence of the pressurized air, and a turbine section to extract energy from the resulting combustion gases. The fan section may include a plurality of fan blades coupled to a fan hub. The compressor section and the turbine section typically include a series of alternating rotors and stators. A rotor generally comprises a rotor disk and a plurality of blades. Diagnostic systems may be used to monitor the health of fan blades and rotor blades. Typically, diagnostic systems use a time-of-arrival sensor to monitor blade health. Time-of-arrival sensors may be well-suited to measure non-integral engine vibrations but, because integral engine order vibrations appear as stationary patterns in the stationary frame, time of arrival sensors are typically not as well-suited to measure integral engine vibrations. Because the majority of engine blade excitations are due to integral engine vibrations, time-of-arrival sensors may be challenged to detect small cracks in engine blades and accurately measure blade health is the sensors are relying on characterizing integral engine order vibrations.